Profile copying mechanism



EA. PARSONS 524,771

PROFILE COPYING MECHANISM Filed July 18, 1938 4 Sheets-Sheet 3.

INVENOR March 11, 1941. I F. A. PARSONS 2,234,775

PROFILE COPYING MECHANISM F. A. PARSONS PROFILE COPYING MECHANISM March11, 1941.

4 Sheets-Sheet 5 Filed July 18, 1938 g; FiglZ.

iii

n Mar- 11,

UNITED STATES PATENT OFFICE PROFILE COPYING MECHANISM Application July18, 1938, Serial No. 219,747

39 Claims.

(This invention relates to machine tools for what is commonly termedcopying operations, where a tool is caused to operate on a work piece toeffect a contour corresponding to the preformed contour of a pattern.

Such operations have in the past required substantially completelyspecialized machines. A primary purpose of. this invention is to providemechanism for copying operations utilizing substantially without changethe transmission and control mechanism of general purpose or standardmachine tools in a manner permitting a minimum of additional mechanismin a form for convenient removal and replacement, whereby toalternatively convert the machine into a copying machine or a generalpurpose machine, and particularly for milling machines.

A further purpose is to effect the desired combination of standard andadditional mechanism in such manner that the additional mechanism orattachment portion will be most readily and easily removable andreplaceable, whereby to increase the effectiveness of the alternativeuse.

A further purpose is to effect an improved organization and arrangementof-tool, tracer, pattern and work supports for a copying machineof themilling machine type, and particularly an organization capable ofutilizing various of the mechanism of a milling machine of generalpurpose type.

For the tracer and tool movements required for copying operations it isusual to utilize a power train including some sort of interrupting orreversing means such as a reverser, usually either hydraulic, electricalor mechanical in its nature, whereby to effectlmovement of the tracerand tool relative to the pattern and work piece respectively, and tointerrupt or reverse such movement. The alternative positions of theinterruptor or reverser are usually effected by power means controlledin accordance with the position of the tracer relative to the pattern,and usually in a manner such that after the tracer point has moved to apredetermined position relative tothe pattern face the interruptor orreverser is shifted to a stop or reverse position as the case may be; Insuch mode of operation any delay in the stopping or reversal of movementfollowing the time when the tracer arrives at said predetermined controlposition, contributes to inaccuracy of copying. Such delays may arisefrom various sources such, for example, as the time required for thetracer to move between said predetermined position efiecting movementtoward the pattern and another position for effecting the other result,the time required for the control means of the power shifter for theinterruptor or reverser to act after the tracer has reached its otherposition, the time required for the power shifter to shift theinterruptor or reverser to the stop or reverse position as the case maybe, and the time required for the interruptor or reverser to act uponthe parts which are driven therethrough to stop or reverse the movementthereof. It is a purpose of the invention to provide trans 10 missionand control means for copying operations in the manner described, but ofimproved construction and organization, to operate with a minimum oftime lag in the desired effect after the tracer point has been moved tosaid predetermined position relative to the pattern.

The reason for use of transmission and control mechanism such as justdescribed is that, although it would be preferable to maintain thetracer in contsant-pressure contact with the pattern as the tracer istraversed across it, it is impracticable to do so. An alternative is toutilize repeated forward movements of the tracer to effect repeatedcontacts with the pattern, whereby the successive contacts repeatedlyposition the 25 tracer point in said predetermined control positionrelative to the pattern as the tracer moves across the face of thepattern. Where other conditions are equal the accuracy of the copyingoperation and the finish on the work piece are each improved inaccordance with a decrease in the time interval between successiveforward movements of the tracer to said predetermined control position.It is a purpose of the present invention to provide transmission andcontrol means for 5 copying operations in the manner described, but witha minimum time interval between successive movements of the tracer topredetermined control positions relative to the pattern.

A further purpose is to provide an improved 40 form of interruptor orreverser control for copying machines, including electric contact meansadapted for control from a tracer device in an improved manner.

A further purpose is to provide transmission and control means forcopying operation including hydraulicinterruptor-reverser positionscontrolled by an electric contact tracer device.

A further purpose is to provide improved transmission and controlmechanism for copying ineludingv means simultaneously reciprocating atracer and tool in a manner to effect continuous reciprocatory cyclesnormally of substantially equal period and equal length.

A further purpose is to provide improved transmission and controlmechanism such as just mentioned in which the reciprocatory cycles areof minimum period.

A further purpose is to provide improved alternatively available controlmechanism such that in the one adjustment thereof the configuration ofthe pattern exclusively controls the depth of operation of the cuttingtool, while in another adjustment the depth of cutting tool operation iscontrolled as just described during a portion of the traversing of thepattern by the tracer, but in another portion the control preventsexceeding a predetermined maximum depth of cut, irrespective of the formof the pattern.

A further purpose is to provide improved transmission and controlmechanism for repeated movements of the tracer across the pattern inseparate or individual paths laterally spaced by predeterminedincrements of cross movement,- particularly in an improved combinationwith the structure for one or more of the previously mentioned objectsor results.

A further purpose is generally to provide improved tracer controlledtransmission and control mechanism to cause relative tool andworkmovement efiecting a form on the work piece corresponding to theform of the pattern associated with the tracer. I

A further purpose is generally to simplify and improve the constructionand operation of machines for efiecting copying operations, and parit'giilarly where cutting is efiected by a rotating The invention includesthe method and structure herein illustrated, described and claimed, andalso such modifications of the method and structure illustrated anddescribed as are equivalent to the claims.

Throughout the specification the same reference characters have beenused to identify the same parts, and in the drawings:

Figure 1 is a partial right side elevation of a milling machineincorporating the invention.

Figure 2 is a partial front elevation of the same machine.

Figure 3 is a partial vertical section, taken approximately along line3-3 of Fig. 1, and enlarged.

Figure 4 is a partial vertical section, taken approximately along line4-4 of Fig. 1, and enlarged.

Figure 5 is a partial vertical section taken approximately along line6-6 of Fig. 4.

Figure 6 is a horizontal section taken approximately along line 6-6 ofFig. 3, also line 6-6 of Fig. '7.

Figure '7 is a vertical section taken approximately along line 1-1 ofFig. 3.

Figure 8 is an enlarged section of a portion of the mechanism at theleft in Fig. 6.

Figure 9 is asection taken on line 99 of Fig. 8. Figure 10 is asemi-diagrammatic section taken along line iii-i0 of Fig. 3 andenlarged.

Figure 11 is an enlarged view of a tracer support shown in Fig. 3.

Figure 12 is a diagram showing the operating relationship of certain ofthe transmission and control mechanism of the machine.

The invention is here shown in the form of an attachment for anotherwise standard milling machine. In Figs. 1, 2 there is shown thetable 20, the column 2| and a portion of the bed or main frame 22 of awell known type of milling machine whic is fully disclosed in my PatentNo. 2,077,435, issued April 20, 1937, and which will therefore not herebe described in detail. The machine includes a rotatable spindle 23,Fig. 5 and an overarm or support structure unitarily denoted by thenumeral 24, Fig. 1, and comprising in this instance horizontally spacedoverarms 24a, 24b horizontally extended above the table 20. The spindle23 and overarm structure 24 are unitarily carried by a verticallymovable spindle carrier 25, of which a portion is shown in Fig. 5, whichmay be rigidly clamped in various positions of vertical adjustmentrelative to table 20. As disclosed in said patent the spindle 23 isprovided with transmission and control mechanism for rotation in eitherdirection at various speeds, and table 20 is provided with transmissionand control mechanism for continuously automatically reciprocating thetable. It will be understood that the machine of said patent isillustrative, but that the invention may be practiced in connection withother machines.

An attachment housing or frame 26 is unitarily carried by the support 24and guided thereon for horizontal cross movement transverse to the pathof longitudinal table reciprocation. Housing 26 may be provided withsuitable gibs for adjustably determining the degree of sliding clearanceon the supports 24a, 24b, and with suitable clamps for rigidly fixingthe housing in desired' positions on the supports, but since such gibsand clamps are well known in various forms they are not here shown.Housing 26 rotatably supports an axially vertical tool spindle 21 and anonrotatable axially vertical tracer spindle 26, these spindles beingspaced apart, in this instance longitudinally with reference to the pathof table reciprocation although they may also be spaced transversely.

Another attachment housing or frame 29 is rigidly fixed on the overarmsupport 24 by the means of a clamp bolt 30. The housing 29 has journaledtherein a rotatable screw 3i which is prevented from axial movement by ashoulder 3la and a collar 32, and extends forwardly to engage a nut 33fixed in the housing 26.

Mechanism is provided for automatic rotation of screw 3|, as follows: Aratchet wheel 34 is fixed on the screw and connected by gears 35, 36with another ratchet wheel 3'! rotatable on a stud 38. Levers 39, 40 arerespectively pivoted on thescrew and stud and respectively carry pivotedratchet dogs 4|, 42 normally urged by a spring 43 in a direction toengage the ratchet wheels. Either or both ratchet dogs may, however, bedisengaged to rest against the abutment pins Ma, 4211. The levers 39, 40are connected by a pivoted link 44 and lever 39 carries a gear segment45 meshing with a gear segment 46 on a pivoted lever 41 having at its.lower end a bar 48 extensibly connected therewith by the means of a slot43a and bolts 49, the bar 48 having fixed therewith an abutment member60 which, in the one direction of movement of table 20, will becontacted and shifted by an abutment screw 5| adjustably fixed with atable dog 52. In the other direction oi table movement the abutment 50will be contacted and shifted by an abutment screw 53 adjustably fixedwith a table dog 54.

whereby to effect a step by step cross feed movement of the housing 26at the ends of the table stroke. The amount of the cross feed movementat either end of the table stroke may be regulated by the adjustment ofabutment screws 53, or by suitably positioning the table dogs, and theratchetdogs 4|, 42 may be selectively disengaged as previously describedto avoid cross feed at either or both ends of the table movement. Whenboth the ratchet dogs 4|, 42 are disengaged the housing 26 may bemanually positioned by a crank, not shown, applied to the squared end ofthe screw 3|. The adjustment of the member 48 on the lever 41 providesfor maintaining of the abutment 59 at the level to contact the abutmentscrews 5|, 53 in various positions of vertical adjustment of the carrier25.

The tool spindle 21 is rotatably driven by any suitable means. In thepresent instance the drive is from the machine spindle, whereby the ratechanger and reverser of the milling machine may be utilized for changeof rate and direction of the tool spindle, the drive being through agear 55,-fixed on the machine spindle, a pinion 56 meshed with gear 55and fixed on a shaft 5'! which is journaled in the housing 29 andprevented from axial movement by any suitable means, a sleeve 58 whichis 'slidably splined with shaft '51 and'journaled in the housing 26,being restrained from axial movement relative thereto by collars 58a,581),. a helical gear 59 fixed on sleeve 58, and a helical gear 60slidabl'y splined on spindle 21, the gear 6|] being prevented from axialmovement by thrust races 60a, 69b engaging suitable thrust faces on thehousing. The shaft 51 and sleeve 58 provide an extensible couplingpermitting the adjustment and feed movement of the housing 26. As analternative drive the spindle 21 may be rotated by a suitable motor (notshown) mounted unitarily with the housing 26 and connected to drive thespindle by suitable gearing (not shown).

The tool spindle 21 may be vertically reciprocated by the means of apiston device denoted in entirety by the numeral 6|. Piston device 6|includes a cylinder 62 fixed with housing 26, a piston 63 and a pistonrod 64, the piston rod having rack teeth 64a. engaging a pinion 65 fixedon a shaft 66 upon which is also fixed a pinion t'l engaging suitablerack teeth 68a on a nonrotatable sleeve 68 which is restrained forvertical movement with the spindle 21 by the means of thrust bearings69, respectively engaging between a shoulder on the spindle and anabutment collar 1|. Various forms of tools such as '02 may be removablyaligned and fixed with the lower end of spindle 21 by any suitablemeans, such as the tapered shank 12a. During operation of the attachmentthe spindle 26 is continuously vertically reciprocated by thepistondevice 6| as will be later explained.

The nonrotatable tracer spindle 28 is connected for verticalreciprocation from piston device 6| along with tool spindle 21. For thispurpose the shaft 66 is extended and carries a pinion 13, which isrotatably adjustably fixed with the shaft by the means of a sleevecollar 13a, Figs. 8, 9 carrying a worm 14 fixed on a shaft 75 which isrotatably adjustable by the means of a suitable wrench, not shown,applied to the squared end a of the shaft, the worm 74 engaging a wormwheel 16 fixed or integral with the extended hub of the pinion I2.Pinion '13 engages suitable rack teeth I'm on a sleeve 11 slidablyengaging the spindle 28 but normally in an axial position relativethereto which is fixed by an abutment collar 18, against which sleeve 11is yieldably pressed by a spring 19 seated at the, one end against asuitable abutment shoulder on the spindle 28. The arrangement is suchthat the tracer spindle 28 is normally vertically reciprocable in unisonwith the tool spindle 21 and with the same length of stroke, but therelative vertical position of the reciprocatory movement of thediflerent spindles may be adjusted by rotatably adjusting the worm wheel16 and if, during the course of its downward movement, the spindle 28meets with resistance it may remain stationary while the sleeve 1'!continues to move downwardly against the resistance of spring 19.

The tracer spindle. 28, at its lower end, carries a tracer devicedenoted in entirety by the numeral 80, Fig. 3. A rod 8| has removablyfixed at its lower end by any suitable means, such as the threaded studportion 8|a, a tracer point 82. A stem portion 8|b extends upwardly tobe housed within a bore 83 in the spindle. The tracer point and tracerrod are resiliently retained in a predetermined position relative tospindle 28 by the means of a yieldable member 84 of any suitableresilient material, Figs. 3, 1 having a bore 840. centering the memberon the tracer rod, to which it is rigidly clamped by a suitable shoulderand a nut 85, the member being centered with the spindle 28 by the meansof a threaded cap 86 inside which the periphery of the member is fittedand which rigidly clamps the member with the spindle. This mountingleaves the member portions intermediate the bore and periphery free .forflexture permitting a certain amount of either vertical or pivotalmovement of the tracer point 82 relative to the spindle, and to decreasethe resistance to such movement the member may be cut away, as by- .thespiral grooves 84b, 840 which extend vertically therethrough, or inother suitable manner.

At its upper end the tracer rod 8| carries a ball shaped electricalcontact member 8'! which is insulated from the rod by the means of aninsulator member 88. A cup shaped contact member 89 is rigidly fixedwith the spindle 28 but insulated therefrom by a member 90. The member89 carries various contacts for engagement by the contact member 81including an adjustable contact screw 89a engageable when the tracerpoint 82 is moved upwardly relative to spindle 28, and adjustablecontact screws 89b, 89c, 89d, 89e respectively engageable in differentdirections of pivotal movement of the tracer point. Unless some pressureis exerted against the tracer point either laterally or vertically nocontact exists at any of the contact points but if the tracer point isdisplaced sufilciently to effect a contact an electric circuit iscompleted whereby to energize a solenoid 9|, Fig. 12. The making andbreaking of the circuit at these contact points controls the verticalreciprocation of the spindles 21, 28, as will be later described.

Referring to the diagram Fig. 12, a pump 92 draws fluid from a reservoir93 and delivers fluid through a valve device 94 and a reverser valve 95to piston device 6|. The valve 95 includes a valve plunger 9511 which iscontinuously urged to In the 'rlght hand position of the valve plunger88a, to the right of the position shown in Fig. 12, the one end of thepiston 88 is connected to the reservoir 88 through achannel 88,.a port8821, an annular groove 850, a port 85d, a channel I88 and a backpressure device I8I of any suitable adjustable pressure type. At thesame time the other end of the piston 83 is connected to receive theoutput of pump 82 through the valve 84, a channel I82, a pressure port88c, an annular groove 85 a port 85g, and a channel I88. The

result is to move the piston 88 in a direction away from the shaft 88,Figs. 3, 12, whereby to move the spindles 21, 28 simultaneouslyupwardly. The valve 84 is any suitable form of shut ofl valve,- adaptedto open or close the passage leading to the reverser valve 88, and todirect the fluid back to the reservoir in the closed position of thevalve. Valve 84a is any suitable form of overload relief valve ofadjustable pressure type.

,In the left hand position of valve plunger 88a, to the left of theposition shown in Fig. 12, the piston 88 is oppositely connected to thepressure port 854: and back pressure valve IN, and the spindles 21, 28are moved simultaneously downwardly,- but in this instance at arelatively slow or feeding rate, since the piston displacement at theend which then receives the pressure fluid is not reduced by the area ofthe piston rod 84.

When the circuit of solenoid 8I is closed the valve member 85a isimmediately shifted'to the right in Fig. 12, and the piston 88 instantlystarts the spindles 21, 28 moving upwardly. when the solenoid circuit isopened the spring 88-immediately shifts the member 85a to the left inFig. 12 and the spindles 21, 28 start moving downwardly. In eitherdirectionof movement the device I8I maintains a controlled back pressureto prevent ovrerun or vibration and to prevent slack or lost motion inthe hydraulic portion of the transmission during reversal.

The solenoid 8I is energized from a suitable line such as I84, Fig. 12,through a line switch I88 and through any of the several contact pointsassociated with the spindle 28 and the tracer device 88, Current iscarried from one contact point of switch I85 to the ball shaped contactmember 81 through a brush I88, Figs. 10, 12, continuously engaging asliding contact I8'I in any of the vertical positions of the spindle 28.Another contact point of switch I85 is connected through solenoid 8| tothe cup shaped contact member 88 by a similar brush I88 andslidingfcontact I88. Each of the brush and sliding contacts are suitablymounted on insulating block's such as the blocks H8, III, Fig. 3. Whenthe tracer point 82, Fig. 3 is not in contact with a pattern, such forexample as the pattern II2, Fig. 3, the tracer rod 8") is held by theyieldable member 84 in such position that the ball contact member 81 isnot engaging any of the contact points 88a, 88b, 88c, 88d, 88c, Figs.10, 12, but contact of the tracer point with the pattern such as mayoccur either in the downward movement of spindle 28, or in the crossmovement of the housing 28, or in the longitudinal movement of table 28,will shift the tracer rod to cause the circuit through the solenoid 8|to be closed through one or another of the contact points, and thespindle 28 will instantly move upward until the tracer point disengagesfrom the pattern and the circuit is broken. Breaking the circuit of thesolenoid, however, starts the spindle 28 moving downwardly once more, aspreviously described, the downward movement continuing until the tracerpoint again contacts the pattern to start another upward movement.

It will be noted that the valve plunger 88A has a central position inwhich no fluid may pass to the piston device 8|, but the valve is neverretained in central position, being continuously urged in one directionor the other. The slightest displacement in either direction effectscorresponding piston movement, and reversal from one to the otherdirection is substantially instantaneous with the making or breaking ofthe tracer circuit.

of the tracer and tool with corresponding alteration in the fast upwardmovement; it is preferable, however, to provide for selective alterationof the downward rate while maintaining a constant upward rate ofmovement, and for this pur-' pose there is provided an adjustablebleeder device, generally denoted as 828, Fig. 12. Bleeder device 828preferably consists of any suitable adjustable volume type of positivedelivery pump, adjustable by a controller 828A, preferably driven fromthe same power source as pump 82, and connected to continuously removefrom the channel 88 the selectively predetermined volume of the fluiddelivered by pump 82, which would otherwise be acting on piston 88during the downward tool movement, During upward tool movement pump 828merely pumps a portion of the waste fluid otherwise passing throughchannel 88 to the reservoir 88 but during downward movement theadjustment of pump 828 determines the rate of such downward movement.While, as stated the adjustable bleeder 828 is preferably a positiveacting pump, any suitable form of adjustable throttle device may also beused. It will be understood that selective alteration of the downwardrate of tool travel, while maintaining a constant relatively rapidupward rate may also be effected by a variety of conventional well knowncircuits, not here shown. The circuit here shown is, however, ofadvantage in that the reverser control is simplified and rendered morecertain, particularly as to the construction and operation of theshiftable valve means.

The mode of operation just described effects a relatively rapidcontinuous vertical reciprocation of the spindles 21, 28 in exactunison, the limit of each downward movement being determined by thecontact of the tracer point with pattern H2, and the upward movement ineach instance continuing until the solenoid circuit is opened. As thetracer point is traversed relative to the pattern the cutter on theother spindle cuts the form of the pattem' in the portion so traversedon the work piece. In the present instance the reclprocatory movement ofthe table and the step by step cross movement of the housing 28 may beutilized to cause the tracer point to automatically traverse the entirearea of any pattern within the limits of the longltudinal'and crossrange available, but either the longitudinal or cross movements may alsobe manually In some instances it is preferable that the form of thepattern should not entirely control the form to be cut in the work pieceH3. If, for example, the form to be copied contains recesses which areso deep that the side thrust or load set up on the tool 12 wouldotherwise become too great, it may be desirable to finish the work insuccessive operations, each limited to a predetermined maximum depth ofout. To limit the downward movement of the pattern and tool, whereby tocorrespondingly limit the load on the cutting tool irrespective of thetotal depth of the pattern recesses, the following mechanism is used:

For the sliding contact I09, Figs. 3, 12, there is provided a secondbrush 4 connected to the same contact point of switch I05 as is thebrush I06, and carried on an insulating member H5, Figs. 3, 10 which isslidably guided forvertical adjustment. Member H5 and brush H4 may beclamped in any adjusted position by a locking screw H6 movable in avertical slot 6a, and may be adjusted downwardly to a position in whichthe brush is below the sliding contact I09 in the lowest patterncontrolled position thereof. In such position the pattern completelycontrols the downward movement of the tracer point and tool. The brushH4 may also be adjusted upwardly to a point where it is contacted by thelower end of the sliding contact mem r I09 when the lower end of tracerpoint 82 is at'a predetermined level above the top of table 20,irrespective of the form of the patern I I2, whereby to complete thesolenoid circuit irrespective of the contacts previously described. Insuch case the pattern will control the downward movement only when vsuchmovement does not extend below the level just mentioned and at thatlevel the downward movement will be reversed by the closing of thesolenoid circuit through the brush lit and sliding cont-act I09. By themechanism just described a work piece requiring deep recesses may befinished in a series of operations, without undue pressure on tool 12,the maximum depth of cut and tool pressure in each operation beinglimited by the level of adjustment of brush lit.

It will be apparent that the removable tracer points 82 and cuttingtools 12 may be of a variety of forms, according to differentrequirements. They should ordinarily be of similar form and size, but incertain instances the one may be larger than the other. If, for example,it is desired to finish the work piece with a roughing and a finishingoperation the tracer point during the roughing operation may besufficiently larger than the cutting tool for the tool to leave thedesired thickness of work material for the subsequent finishing. In someinstances it may be desirable that the tracer point be smaller than thecutting tool, whereby to finish the work piece in a form correspondinglylarger than the pattern, as, for example, where the part finished is adie in which allowance must be made for shrinkage of metal in cooling.

The operation as previously described contemplates reversal of tracermovement from either lateral or vertical displacement of the tracerpoint. Reversal'from lateral movement is included principally as asafety feature, operathe tracer has moved above the obstruction, atwhich time normal operation of continuous vertical tracer reciprocationin substantially equal cycles will be resumed. Where there are no suchobstructions presented by the pattern form the tracer and tool. controlmay be solely from the vertical tracer movement, and in such case thetracer may be prevented from side movement, as, for example, by usingsubstitute screws 89b, 89c, 8901, 89c formed of insulating material andset forward to prevent lateral displacement of the tracer, or bymodification of the tracer mounting to prevent lateral displacement, orby other suitable means. I

In the device here'disclosed, and particularly if the reversal of tracermovement is controlled only by vertical tracer displacement as justmentioned, the form of the pattern may be automatically copied on thework piece with the highest degree of accuracy. The accuracy isprimarily clue to the features of the construction and operation whichprovide that the downward movement of the tracer and tool shall bestopped and reversed substantially instantly when the contact iseffected which energizes the solenoid 9|. Since the valve plunger 95a issubstantially frictionless and requires only the slightest movement fromforward to reverse positions, or vice versa, the solenoid may beconstructed with a very light armature, requiring a minimum of time tobe energized. Moreover, since the start of the upward movement does notrequire the opening of any circuit there, is no lag caused by sparkingor arcing of the contact points. The back pressure valve Illlcontributes to avoiding lag in reversal by preventing time loss required,to build up pressure in the reverse direction on piston 63. Inaddition, the transmission is such that the parts to be reversed aresubstantially frictionless, and of substantially no inertia,particularly since there are no rotating parts except the slow speedconnecting shaft 66. All of the features just mentioned furthercontribute to accuracy by permitting repeated cycles of verticalreciprocation of very small period, whereby the 4 copying positions orpoints are relatively very closely spaced on the work piece during thetraversing of the workpiece by the cutter. The latter result is furtherassisted by the relatively fast reverse or upward movement, andparticularly because the complete forward and reverse cycle is effectedmerely by making and breaking a contact, that is to say with a minimumof tracer control movement.

The yieldable tracer supporting member 84 may be constructed to presentvery little resistance to tracer movement, and in such case the patternssuch as H2 may be made relatively weak or soft material such as plasterof paris, or of wood. No cutting is ordinarily done during the upwardmovement of the tracer and upward movement may therefore, be arelatively very rapid rate, whereby the tracer point 'may operateagainst substantially vertical surfaces.

Since the cross movements take place at the end of the-table stroke theymay ordinarily be effected when the tool is outside the cutting zone. Itwill be apparent that the pumps 92, 920 and valves 94, 95, ll, etc. maybe positioned at any suitable point in the housing 26, the lower portionof the housing forming the reservoir 93, as indicated in Fig. 3. In suchcase the pumps may be driven by any suitable train, not shown, fromshaft 51. The reservoir 93, or both the pumps and reservoir, and certainof the other mechanism may. instead, be separate from the housing 28,and in such case the piston circuit will be completed by suitable 'pipechannels, flexible where necessary, in any suitable well known manner.

What is claimed is:

1. In a copying attachment for milling machines having a rotatable toolspindle, a reciprocable table and a main frame supporting said spindleand table, the combination of an attachment frame'removably supportedfrom said main frame, a rotatable supplemental tool spindle and a tracermember each supported from said attachment frame for unitary removaltherewith and spaced apart in a direction transverse to the axis of thesupplemental spindle, and means under the control of. said tracer memberfor movement of said supplemental tool spindle and tracer memberrelative to said attachment frame in substantially mutually parallelpaths transverse to the path of reciprocation of said table.

2. In a copying attachment for milling machines having a main frametogether with a reciprocable table and a rotatable tool spindle eachsupported from said main frame for relative bodily movement of saidtable and spindle, the combination of an attachment frame removablysupported from said main frame and in a manner to participate in saidrelative bodily spindle and table movement, a rotatable supplementaltool spindle and a tracer member each supported from said attachmentframe for said relative bodily movement therewith, said supplementalspindle and tracer member being spaced apart in a direction transverseto the supplemental spindle axis, and means under the control of saidtracer member for movement of said supplemental spindle and tracermember relative to the attachment frame in substantially mutuallyparallel paths transverse to the path of reciprocatory movement of saidtable.

3. In a copying attachment for milling machines having a rotatable toolspindle, a reciprocable table and a main frame supporting said spindleand table, the combination of an attachment frame removably supportedfrom said main frame, a rotatable supplemental tool spindle and a tracermember each supported from said attachment frame for unitary removaltherewith and spaced apart in a direction transverse to the axis of thesupplemental spindle, said supplemental spindle and tracer member eachbeing reciprocably movable relative to said attachment frame in pathssubstantially parallel to the axis of the supplemental spindle andtransverse to the path of reciprocation of said table, and transmissionmechanism under control of said tracer member to effect saidreciprocatory movement of said supplemental spindle and tracer member.

4. In a copying attachment for milling machines having a rotatable toolspindle, a reciprocable table and a main frame supporting said spindleand table,. the combination of an attachment frame removably supportedfrom said main frame, a rotatable supplemental tool spindle and a tracermember each supported from said attachment frame for unitary removaltherewith and spaced apart in a direction transverse to the supplementalspindle axis, said supplemental tool spindle and tracer member beingconnected for mutually corresponding reciprocatory movement relative tosaid attachment frame in substantially parallel paths transverse to thepath of reciprocation of said table, transmission mechanism for saidmutually corresponding reciprocatory movement including a shiftablereverser device, power means for shifting said reverser device, andmeans controlling the connection of said power means in accordance withmovement of said tracer member.

5. In a copying attachment for milling machines having a main frame, ahorizontally reciprocable table and a main spindle each supported fromsaid main frame, and a slideway at a level above said table andsupported from said main frame, the combination of a second frame guidedby said slideway for horizontal bodily adjustment above said table in apath transverse to the path of table reciprocation, a second toolspindle and a tracer member spaced apart in a direction transverse tothe second spindle axis and each supported from said second frame forbodily adjustment therewith, said second spindle and tracer member beingconnected for mutually corresponding vertical reciprocatory movementrelative to said second frame and in substantially parallel paths, meansfor said bodily movement of said second frame, a transmission for saidvertical reciprocatory movement of said spindle and tracer member, andmeans controlling said transmission from said tracer member during thedownward portion of reciprocatory movement thereof.

6. In a copying attachment for milling machines having a main frame, ahorizontally reciprocable table and a main spindle supported from saidmain frame, the combination of a, second frame guided for horizontalbodily adjustment above said table in a path transverse to the path oftable reciprocation, a second spindle and a tracer member spaced apartin a direction transverse to the spindle axis and each carried by saidsecond frame for said bodily adjustment therewith, said second spindleand tracer member being connected for mutually correspondingreciprocatory movement relative to said second frame and in parallelpaths, a transmission for said reciprocatory movementof said secondspindle and tracer member, power means for said bodily adjustment ofsaid second frame including dog means associated with said table, andmeans controlling said tranmission from said tracer member to effectsaid reciprocatory movement.

7. In a copying attachment for milling machines including a main frame,a table supported from said frame for horizontal reciprocation, and aslideway at a level above said table and supported from said main frame,the combination of a second frame guided by saidwlideway for horizontalbodily adjustment above said table in a path transverse to the path oftable reciprocation, a tool spindle and a tracer member spaced apart ina direction transverse to the spindle axis and each carried by saidsecond frame for bodily adjustment therewith, said spindle and tracermember being connected for mutually corresponding vertical-reciprocatorymovement relative to said second frame in substantially parallel paths,means for said bodily moveframe and table whereby to simultaneouslyadjust the spacing of said spindle and tracer member above said table.

8. In a copying attachment for milling machines having a main frame, atable supported from said frame for horizontal reciprocation, ahorizontal main spindle rotatably supported at a level above said tableand axially transverse to the path of table movement, and overarm meansfor the support of arbors associated with said main spindle including anoverarm supported from said main frame above said table, said overarmmeans providing adjusting guide surfaces extended in a directionparallel to the axis of said main spindle, the combination of anattachment frame removably located in a position above said tabledetermined by said surfaces, a rotatable attachment spindle and a tracermember each supported from said attachment a level above said table andaxially transverse to the path of table movement, and overarm meansincluding an overarm supported from said main frame above said table,said overarm means providing surfaces extended in a direction parallelto the axis of said main spindle, the combination of anattachment frameremovably located in a position above said table determined by saidsurfaces, a rotatable attachment spindle and a tracer member eachsupported from said attachment frame and spaced apart in a directiontransverse to the attachment spindle axis, said attachment spindle andtracer member being mutually correspondingly reciprocable relative tosaid attachment frame in substantially parallel paths transverse to thepath of table reciprocation, and means controlling said correspondinglyreciprocable movement from said tracer member during reciprocatorymovement thereof, said overarm means surfaces providing a slideway forpositioning said attachment frame in various adjustment positions in apath parallel with the axis of said main spindle.

10. In a milling machine having a rotatable tool spindle, areciproc'able table and a main frame supporting said spindle and table,the combination of a copying attachment frame removably supported fromsaid main frame, a rotatable supplemental tool spindle and a tracermember each supported from said attachment frame and spaced apart in adirection transverse to the supplemental spindle axis, said supplementalspindle and tracer member being mutually correspondingly reciprocablerelative to said attachment frame in substantially parallel pathstransverse to the path of reciprocation of said table, and meanscontrolling said corresponding reciprocation from said tracer memberduring reciprocatory movement thereof, the support for said attachmentframe from said main frame providing for relative bodily adjustment ofsaid frames in a direction transverse to the path of reciprocation ofsaid table.

11. Ina milling machine having a rotatable tool spindle, ,a reciprocabletable and a main frame supporting said spindle and table, thecombination of a copying attachment frame removably' supported from saidmain frame, a rotatable supplemental tool spindle and a tracer membereach supported from said attachment frame 1 said tracer member duringmovement thereof relative-to said attachment frame and in variouspositions of said relative adjustment of the attachm'ent frame.

12. In a milling machine having a rotatable tool spindle, a reciprocabletable and a main frame supporting said spindle and table, thecomblnation of a copying attachment frame removably supported from saidmain frame, a rotatable supplemental tool spindle and a tracer membereach supported from said attachment frame for unitary removal therewithand spaced apart in a direction transverse to the supplemental spindleaxis, said supplemental spindle and tracer member being connected formutually corresponding movement relative to said attachment frame insubstantially parallel paths transverse to the path of reciprocation ofsaid table, and means controlling said supplemental spindle and tracermember movement from said tracer member during said movement thereof,said connection of the supplemental spindle and tracer member includingmeans for relative adjustment thereof in said parallel paths.

13. In a milling machine having a main frame together with areciprocable table and a rotatable tool spindle each supported from saidmain frame for relative bodily movement thereof, the

combination of a copying attachment frame removably supported from saidmain frame to participate in said relative bodily spindle and tablemovement, a rotatable supplemental tool spindle and a tracer member eachsupported from said attachment frame for said relative bodily movementtherewith, said supplemental spindle and tracer member being spacedapart in a direction transverse to the supplemental spindle axis andconnected for mutually corresponding reciprocatory movements relative tothe attachment frame in substantially parallel paths transverse to thepath of reciprocatory movement of said table, and means controlling saidcorresponding reciprocatory movement from said tracer member duringreciprocatory movement thereof, said connection of the supplementalspindle and tracer member including means for relative adjustmentthereof in said parallel reciprocatory paths.

' 14. In a milling machine having a main frame together with areciprocable tablerand a rotatable tool spindle supported from said mainframe for relative bodily movement of said table and spindle, thecombination of an attachment frame removably supported from said mainframe to participate in said relative bodily spindle and table movement,a rotatable supplemental tool spindle and a tracer member each supportedfrom said attachment frame for said relative bodily movea directiontransverse to the aids of said spindle, means controlling saidcorresponding recipro catory movement from said tracer member duringreciprocatory movement thereof, and a ment therewith, said supplementalspindle and tracer member being spaced apart in a direction transverseto the supplemental spindle axis and connected for mutuallycorresponding reciprocatory movements relative to the attachment framein substantially parallel paths transverse to the path of reciprocatorymovement of said table, and means controlling said correspondingreciprocatory movement from said tracer member during reciprocatorymovement thereof, said connection of the supplemental spindle and tracermember including means for relative adjustment thereof in saidcorresponding reciprocatory paths, the support for said attachment frameproviding for adjustment thereof in a direction transverse to the pathof reciprocatory table movement while maintaining said control from saidtracer member in various positions of such adjustment.

15. A copying machine including a main frame, a table supported fromsaid frame for horizontal reciprocation, a horizontal slideway at alevel above said table and supported from said main frame, a secondframe above said table and guided in said slideway for horizontal bodilyadjustment in a path transverse to the path of table reciprocation, atool spindle and a tracer member spaced apart in a direction transverseto the spindle axis and each carried by said sec-- ond frame for saidbodily adjustment therewith, said spindle and tracer member beingconnected for mutually corresponding reciprocatory movement insubstantially parallel paths transverse to the path of tablereciprocation, means for said bodily;movement of said second frame, atransmission for said mutually corresponding reciprocatory movement ofsaid spindle and tracer member, and means controlling said transmissionfrom said tracer member during the reciprocatory movement thereof, saidmain frame providing members adjustable for changing the relativevertical spacing of said slideway and table whereby to adjust thespacing of said second frame above said table, the connection of saidspindle and tracer member including means for relative adjustmentthereof in said corresponding reciprocatory paths.

16. In a milling machine having a main frame and a reciprocable table,the combination of a copying attachment frame removably supported onsaid main frame for bodily movement relative thereto in a pathtransverse to the reciprocatory table movement, a rotatable tool spindleand a tracer member each supported from said attachment frame for bodilymovement therewith and connected for mutually correspondingreciprocatory movement relative to said attachment frame .insubstantially parallel paths transverse to the path of reciprocatorytable movement, said spindle and member being spaced apart in powertrain for effecting said bodily movement of the attachment frame, saidpower train includmember connected for substantiallycorrespondmrz'avable tool and work supports, the combination ingreciprocatory movement in mutually parallel paths, said spindle andmember being also relatively movable, a transmission for saidreciprocatory movement including a fluid operable piston device,andcontrol means for said transmis- 6 sion including shiftable reverservalve means controlling the direction of movement of said piston device,a solenoid device for shifting said reverser valve means, to effect onedirection of said piston device movement, and electric contact elementscontrolling the energizing of said solenoid device and relativelymovable to circuit closing position upon said relative spindle and memiber movement, and means continuously operative to urge shifting of saidreverser valve means to effect the other direction of said piston devicemovement.

18. In a copying machine the combination of a tool support and a worksupport relatively reciprocable in a straight line path, one of saidsupports being reciprocable in another path transverse to the firstmentioned path, a tracer member reciprocable substantiallycorrespondingly to the last mentioned support, transmission means forsaid transverse reciprocatory movement including a shiftable reverserdevice, means con-' tinuqusly urging said reverser device in onedirection of its shifting movement, and other means under the control ofsaid tracer member for intermittently urging said reverser device in theother direction of its shifting movement.

19. In a copying machine the combination of a tool support and a worksupport relatively reciprocable in a straight line-path, one of saidsupports being reciprocable in another path transverse to the firstmentioned path, a tracer member reciprocable substantiallylcorrespondingly to the last mentioned support, transmission means forsaid transverse reciprocatory movement including a fluid operable pistondevice and a pressure fluid source, control means for said transversereciprocatory movement including reverser, valve means shiftable forchangin the direction of operation of said piston d vice, meanscontinuously urging said reverser =va ve means in a direction to effectthe one direction of said transverse reciprocatory movement, and othermeans under the control of said tracer member. for intermittently urgingsaid reverser valve means in a direction to effect the other directionof said reciprocatory movement.

20. In a copying machine the combination of a tool support and a worksupport relatively reciprocable in a straight line path, one of saidsupports being reciprocable in another path transverse to the firstmentioned path, a tracer member reciprocable substantiallycorrespondingly to the last mentioned support, transmission means forsaid transverse reciprocatory movement including a shiftable reverserdevice, means continuously urging said reverser devicein a direction toeffect one direction of said transversereciprocatory movement, and meansfor intermittently shifting said reverser in a direction to effect theother direction of said transverse reciprocatory movement includingelectric contract elements relatively movable to open and closed circuitpositions under the control of said tracer member.

21. In a copying machine having relatively of transmission means forsaid relative movement including a fluid operable reversible motordevice and reverser valve means shiftable for controlling the directionof motor actuation; and means for shifting said reverser valve meansincluding a tracer member movable substantially correspondingly to oneof said supports and power means under the control of said tracermember, said transmission means including means continuously operativeto maintain simultaneously opposed material fluid pressures on theopposite pressure faces of said motor.

22. In a copying machine having relatively movable tool and worksupports, the combination of transmission means for said relativemovement including reverser means shiftable for controlling thedirection of such movement together with means operative to effect arelatively higher speed of said relative movement in the one directionposition of said reverser means than in the other,

- and means for shifting said reverser means ineluding meanscontinuously urging said reverser means toward the direction positioneffecting the relatively lower speed, a tracer member movablesubstantially correspondingly to one of said supports, and means underthe control of said tracer member for intermittently shifting saidreverser means to the direction position effecting the relatively higherspeed.

23. In a copying machine having relatively movable tool and worksupports, the combination of a tracer member movable substantially inaccordance with the movement of one of said supports, transmissionmechanism for said tool and work support movement including a fluidoperable reversible motor device and reverser valve means shiftable todifferent direction positions, means continuously urging said reverservalve means toward one of said direction positions,

means under the control of said tracer member for intermittentlyshifting said reverser valve means to its other position and meansassociated with said transmissions and operative in either directionposition of said reverser valve means to maintain simultaneously opposedfluid pressure on. the opposite pressure faces of said motor device.

24. In a copying machine having relatively movable tool and worksupports and a tracer member movable substantially in accordance withthe movement of one of said supports, the combination of transmissionmechanism for said tool and work support movement including a fluidoperable reversible motor device and reverser valve means shiftable to"different direction positions together with means operative in eitherdirection position of said reverser valve means to maintainsimultaneously opposed fluid pressure on the opposite pressure faces ofsaid motor device and means operative to effect a relatively higherspeed of said tool and work support movement in one of the directionpositions of said reverser valve means than in the other thereof, andmeans under the control of said tracer member for intermittentlyshifting said reverser valve means to the direction position effectingsaid relatively high speed.

25. In a copying machine having a work support and a tool supportrelatively movable toward one another in a forward copying direction andalternatively in a reverse direction and a tracer member movablesubstantially in accordance with the movement of one of said supports,the combination of power operable transmission mechanism for saidrelative support movement including reverser means shiftable to forwardand reverse support direction positions, control means operative underthe control of said tracer memher to shift said reverser means to saidreverse direction position during forward movement of said supports, andother control means alternatively operable during said forward movementto shift said reverser means to said reverse direction position at apredetermined minimum spacing of said. supports during said forwardmovement thereof.

26. In a copying machine having a work support and a tool supportrelatively movable toward one another in a forward direction andalternatively in a reverse direction and a tracer member movablesubstantially in accordance with the movement of one of said supports,the combination of power operable transmission mechanism for saidsupport movement including reverser means shiftable to forward andreverse support direction positions, control means operative under thecontrol of said tracer member to shift said reverser means to saidreverse direction position during forward movement of said supports, andother control means alternatively operable to shift said reverser meansto said reverse position at a predetermined minimum spacing of saidsupports during said forward movement thereof, said other control meansbeing adjustable to vary the support spacing predetermined thereby.

27. In a copying machine the combination of a work support and a toolsupport relatively movable toward one another in a forward direction andalternatively in a reverse direction and a tracer member movablesubstantially in accordance with the movement of one of said supports,power operable transmission mechanism for said support movementincluding reverser means shiftable to forward and reverse supportdirection positions, and control means operative to shift said reversermeans to effect said forward and reverse support directions of movementin repeated reciprocatory cycles including means continuously urgingsaid reverser means toward its forward di rection position and meansoperative under the control of said tracer member for intermittentlyshifting said reverser to said reverse position, and other meansalternatively operable for shifting said reverser to reverse position ata predetermined minimum spacing of said supports.

28. In a copying machine having a work support and a relatively movabletool support, the combination of transmission mechanism for said supportmovement in repeated cycles of alternate copying direction toward oneanother and reverse direction, a first control device for saidtransmission including pattern and tracer members relatively movablesubstantially in accordance with the support movement to variablydetermine the limit of said copying direction of movement in accordancewith variations in the configuration of said pattern member, and othercontrol means alternatively operable to determine said limit of copyingdirection of movement for some of said cycles irrespective of theconfiguration of said pattern member and at a predetermined minimumspacing of said supports.

29. In a copying machine having a work support anda relatively movabletool support, they combination of transmission mechanism for said supprt movement in repeated cycles of alternate copying direction toward oneanother and reverse direction, a first control device for saidtransmission including pattern and tracer members relatively movablesubstantially in accordance with the support movement to variablydetermine the limit of said copying direction of movement in accordancewith variations in the configuration of said pattern member, and othercontrol means alternatively operable to determine said limit of copyingdirection of movement for some of said cycles at a predetermined minimumspacing from one of said supports and irrespective of the configurationof said pattern member, said other control means being adjustable toalter said predetermined minimum spacing.

30. In a copying machine the combination of a tracer member, a powertransmission for movement of said tracer member alternatively inopposite directions including a pressure fluid source, shiftablereverser valve means and a fluid operable motor, means continuouslyurging said reverser valve means in a direction effecting one directionof said tracer movement, and means under the control of said tracermember for shifting said reverser valve in the other direction.

31. In a copying attachment for milling machines having a main frametogether with a reciprocable table and a rotatable main spindlesupported from said main frame for relative bodily movement of saidtable and main spindle in a direction transverse to the path of tablereciprocation, the combination of an attachement frame removablysupported from said main frame in a manner to participate in saidrelative bodily table and main spindle movement, a rotatable attachmentspindle and a tracermember each associated with said attachment frame toparticipate therewith in said relative bodily table and main spindlemovement, said attachment spindle and tracer member being spaced apartin a direction transverse to the direction of said relative bodilymovement and each reciprocable in substantially mutually parallel pathstransverse to the path of reciprocatory movement of said table, andmeans under the control of said tracer member for efmovement of saidtable and main spindle in a direction transverse to the path of tablereciprocation, the combination of an attachment frame removablysupported from said main frame in a manner to participate in saidrelative bodily table and main spindle movement, a rotatable attachmentspindle and a tracer member each associated with said attachment frameto participate therewith in said relative bodily table and main spindlemovement, said attachment spindle and tracer member being spaced apartin a di rection transverse to the direction of said relative bodilymovement and each reciprocable in subtantially mutually parallel pathstransverse to the path of reciprocatory movement of said table,transmission mechanism for said tracer member and attachmentspindlereciprocable movement including reverser means supported from saidattachment frame and adjustable for forward and reverse directioneffects, and means operable under the control of said tracer member foradjusting said reverser means.

33. In a copying attachment for milling machines having a main frametogether with a reciprocable table and a rotatable main spindlesupported from said main frame for relative bodily movement of saidtable and main spindle in a direction transverse to the path of tablereciprocation, the combination of an attachment frame removablysupported from said main frame in a manner to participate in saidrelative bodily table and main spindle movement, a rotatable attachmentspindle and a tracer member each associated with said attachment frameto participate therewith in said relative bodily table and main spindlemovement, said attachment spindle and tracer member being spaced apartin a direction transverse to the direction of said relative bodilymovement and each reciprocable in substantially mutually parallel pathstransverse to the path of reciprocatory movement of said table,transmission mechanism for said tracer member and attachment spindlereciprocable movement including a reverser device ad- Justable toforward and reverse direction positions, means continuously urging saidreverser device toward one of said positions, and means operable underthe control of said tracer member for shifting said reverser device tothe other of said positions.

34. In 9. copying attachment for milling machines having a main frametogether with a reciprocable table and a rotatable main spindle eachsupported from said main frame for relative bodily movement of saidtable and main spindle in a direction transverse to the path of tablereciprocation, the combination of an attachment frame removablysupported from said main frame in a manner to participate in saidrelative bodily table and main spindle movement, a rotatable attachmentspindle and a tracer member each associated with said attachment frameto participate therewith in said relative bodily table and main spindlemovement, said attachment spindle and tracer member being spaced apartin a direction transverse to the direction of said relative bodilymovement and each reciprocable in substantially mutually parallel pathstransverse to the path of reciprocatory movement of said table,transmission mechanism for said tracer member and attachment spindlereciprocable movement including a reverser device adjustable to forwardand reverse direction positions, means operable under the control ofsaid tracer member for adjusting said reverser device alternately to itsdifferent positions whereby to effect tracer member controlledreciprocable movement of said tracer member and attachment spindle, andother control means for adjusting said reverser device alternatively toits different positions whereby to efiect said reciprocable movement ofthe tracer member and attachment spindle independently of the tracermember control.

35. In a copying attachment for milling machines having a main frametogether with a reciprocable table and a rotatabk main spindle eachsupported from said main frame for relav tive bodily movement of saidtable and main spindle in a direction transverse to the path of tablereciprocation, the combination of an attachment frame removablysupported from said main frame in a manner to participate in saidrelative bodily table and main spindle movement, a rotatable attachmentspindle and a tracer member each associated with said attachmentf-rameto participate therewith in said relative bodily table and main spindlemovement, said-attachment spindle and tracer member being spaced apartin a direction transverse to the direction of said relative bodilymovement and each reciprocable in substantially mutually parallel pathstransverse to the path of reciprocatory movement of said table,transmission mechanism for said tracer member and attachment spindlereciprocable movement including a fluid oper- Bit able motor andshiftable reverser valve means, and means under the control of saidtracer member for shifting said reverser valve means. 36. In a copyingattachment for milling machines having a main frame together with areciprocable table and a rotatable main spindle each supported from saidmain frame for relative bodily movement of said table and main spindlein a direction transverse to the path of table reciprocation, thecombination of an attachment frameremovably supported from said mainframe in a manner to participate in said relative bodily table and mainspindle movement, a rotatable attachment spindle and a tracer membereach associated with said attachment frame to participate therewith insaid relative bodilytable and main spindle movement, said attachmentspindle and tracer member being spaced apart in a direction transverseto the direction of said relative bodily movement and each reciprocablein substantially mutually parallel paths transverse to the path ofreciprocatory movement of said table, a transmission for said tracermember and attachment spindle reciprocable movement including ashiftable reverser, means for shifting said reverser including electriccontact elements adjustable to open and closed contact positions, andmeans under the control of said tracer member for adjusting said contactelements.

37. in a copying machine the combination of a tool support and a worksupport relatively movable in a predetermined path, a tracer inernberreciprocable together with one of said supports in substantiallymutually parallel paths transverse to the first mentioned path,mechanism for effecting said transverse reciprocatory movement of thelast mentioned support and said tracer member including a power trainfor one direction thereof and comprising a device shiftable foralternatively connecting or interrupting said power train, meanscontinuously urging said shiftable device toward a position connectingsaid power train, a pattern member adapted to be contacted by saidtracer member during the last mentioned direction of movement thereof,and means under the combined control of said tracer member and patternmember for shifting said device to a position interrupting said powertrain upon said contact of the tracer and pattern member, said mechanismalso including means operable for the other direction of movement insaid transverse paths upon interruptlon of said power train, whereby toeffectcontinuous reciprocatory movement of said last mentioned supportand tracer member.

38. A copying machine including a main frame, a table supported fromsaid frame for horizontal reciprocation, a horizontal slideway at alevel above said table and supported from said min frame, a second frameabove said table and guided in said slideway for horizontal bodilyadjustment in a path transverse to the path of table reciprocation, atool spindle and a tracer member spaced apart in a direction transverseto the spindle axis and each carried by said second frame for saidbodily adjustment therewith, said spindle and tracer member beingconnected for mutually corresponding reoiprocatory movement insubstantially parallel paths transverse to the path of tablereciprocation, means for said bodily movement of said second frame, saidconnection of said spindle and tracer member including a driver membercommon to said spindle and tracer member and a plurality of drivenmembers respectively individual to the spindle andto the tracer member,a transmission for actuating said driver member to efiect said mutuallycorresponding reciprocatory movement. of said spindle and tracer member,and means controlling said transmission from said tracer member duringthe reciprocatory movement thereof, said main frame providing membersadjustable for changing the relative vertical spacing of said slidewayand table whereby to adjust the spacing of said second frame above saidtable, the connection of said spindle and tracer member including meansfor relative adjustment thereof in said corresponding reciprocatory'paths.

39. A copying machine including a stationary frame, a tablesupported-from said stationary frame, a second frame supported from saidstationary frame at a level above said table, a rotatable tool spindleand a tracer member spaced apart in a direction transverse to the axisof said spindle and each carried by said second frame, a connectionbetween said spindle and tracer member for mutually correspondingreciprocable movement thereof relative to said second frame in pathssubstantially mutually parallel with said spindle axis, said connectionincluding a driver member common to said spindle and tracer member and aplurality of driven mem-- bers respectively individual to the spindleand to the tracer member, a transmission for actuating said drivermember to effect said mutually corresponding spindle and tracer membermovement, and means controlling said transmission from said tracermember during said reciprocable movement thereof, said main frame havingslideways associated therewith for relative reciprocation of said tableand second frame in a substantially horizontal path and for relativeadjustment thereof in a path transverse to the path of said relativereciprocation, the connection of said spindle and tracer memberincluding means for relative adjustment thereof in said mutuallycorresponding reciprocable paths.

FRED A. PARSONS.

